The present invention relates to a projection type image display system, projector, program, information storage medium and image projection method which can change a projection position.
Projection type image display systems such as liquid crystal projectors and the like have been used in classrooms, movie theaters, meeting rooms, exhibition grounds and domestic living rooms.
When an image is projected using a liquid crystal projector or the like and if there is an obstacle between an image projecting section and a projection plane, the image will not well been viewed by the obstacle on which the projected light impinges or which obstructs the view.
For example, a domestic living room is usually used not only by the user of a liquid crystal projector or the like, but also by the user's family. Even if the user has secured any larger area of wall surface as a projection area, anyone of his or her family may place a furniture or houseplant in front of that wall surface such that the furniture or houseplant will hide part of the projection area intended by the user.
Moreover, if a liquid crystal projector or the like is used to project a product introduction image or an advertisement image in an exhibition ground or the like, the image may be partially hidden behind any person who has unintentionally entered the projection area.
In such a case, it is usual that the user moves the liquid crystal projector or the like or changes the direction of projection from the liquid crystal projector or the like to avoid the obstacle and to project the image properly. However, the movement of the liquid crystal projector or the like is troublesome while at the same time, the calibration must be tried again.
When the liquid crystal project or the like is used to project an image, moreover, the user may want to project the image onto the desired portion of the projection area depending on the situation in the projection.
For example, in a room into which a living room and kitchen are unified, the user may usually project an image onto the wall of the living room and sometimes want to project another image illustrating a recipe onto the wall of the kitchen.
For presentation, a right-handed presenter may more easily point an image through a pointer when the image is displayed on the right side as viewed from audience while a left-handed presenter may more easily point the image through the pointer when the image is displayed on the left side as viewed from the audience.
In such a case, it is preferred that the user shifts the image projection position to perform a more effective presentation. However, it takes time that the projector is manually adjusted in projection position and re-calibrated each time when one presenter is replaced by another.
In order to display an image intended by the user, furthermore, it is necessary that the color and brightness of an image are corrected in consideration of the influences of ambient light (illuminating light or sunlight) and projection plane.
In recent years, the partial illumination has been adopted even in home. If the projection position has been changed without change of the settings in the liquid crystal projector or the like, therefore, the image appearance intended by the user may be highly varied since the influence of the ambient light to the image is variable depending on the projection position.